SU1374367A1 - Voltage converter with asymmetry protection - Google Patents

Abstract

The invention relates to converter equipment and can be used in power supplies of electronic equipment. The purpose of the invention is to increase reliability and speed. The converter contains a driving pulse generator 1, an orypto-pulse modulator 2, a control signal processing logic block 3, a push-pull power amplifier 6, power transistors 4, 5. Running a current sensor 8 on a resistor , connecting the combined collectors to the positive input terminal and connecting one end of the current sensor to the negative input terminal provides the possibility of reducing the paths of the impulse noise, easier s components. 3 il. with y

Description

teMk

(

-L ... j

W

The invention relates to converter equipment and can be used in power supplies of electronic equipment, automation devices, in particular in transistor static voltage converters,

The purpose of the invention is to increase reliability, reduce inertia, reduce overall dimensions, simplify the device.

Fig, shows a functional diagram of the device; Fig. 2 illustrates the execution steps of the logic processing unit, the control signal; Fig. 3 shows timing diagrams explaining the operation of the device.

The device contains a master oscillator 1, the output of which is connected to the first input of pulse-width modulator 2. containing a comparator and integrator, and with the first input of control logic logic processing unit 3, the output of a pulse-width modulator 2 is connected to the second input of the block 3 logic processing of the control signal, the outputs of which are respectively connected to the bases and emitters of the transistors 4 and 5 of the push-pull power amplifier 6, the emitters of these transistors are connected to the corresponding end of the primary winding the input transformer 7, and the collectors are combined and connected to the positive input terminal of the converter, and the negative input terminal through the current sensor 8 is connected to the middle terminal of the primary winding of the output transformer 7, the threshold element 9 connected to the resistors and the transistor is connected in parallel to the current sensor 8 element is connected to the second input of the pulse-width modulator 2, the third input of which receives the control signal from the secondary winding of the output transformer 7,

The control signal processing unit 3 (FIG. 2) contains a bipolar signal converter, performed on a D-trigger iO and two elements 2I-HE 11 and a transformer 12, a two-channel preamplifier 13 implemented on transistors, resistors and capacitors.

ten

15

20

25

thirty

35

40

45

50

55

The device works as follows.

The first stage - there is no asymmetry. The clock frequency of the driving generator of rectangular pulses (Fig. 3) is fed to the first input of the pulse-width modulator 2 (to the input of the integrator). A ramp signal is received at the output of the integrator (Fig. 3). This signal is fed to the input of element 2-NOT, Neither the second input of which receives a signal from the output of the threshold element 9, in the absence of asymmetry, the output of which always contains the signal G of the digital integrated circuit. At the output of the element, we obtain a signal modulated by a pulse width modulator (FIG. 3) that is inverted and fed to the second input of the logic control unit 3 of the control unit, the first frequency of which receives the clock frequency from the master oscillator 1 rectangular pulses In block 3 of the logical processing of the control signal, the signal from the output of the pulse-width modulator is converted into two inverse bipolar signals relative to each other (Fig.). Each of these signals is fed to the bases and em panthers transistors 4 and 5, a push-pull power amplifier 6. The push-pull power amplifier 6 amplifies the incoming signals and supplies them to the half windings of the primary winding of the output transformer 7. A signal is formed on the current sensor 8 (FIG. 3) that goes to the base of the transistor of the threshold element 9, and the same signal goes to the emitter of the transistor weakened. At the output of the threshold element 9, a signal is obtained whose level is equal to 1 digital integrated circuit.

The second stage is asymmetry. Asymmetry arises due to the different parameters of the transistors of the push-pull power amplifier 6, different ohmic resistance and inductance of the primary windings of the transformer 7, errors in the operation of the comparator.

For any of these reasons, an asymmetry arises and currents of magnetisation of the core of the output transformer 7 appear, and the signal on

current sensor 8 is varied and takes the form shown in Fig. Z.

If the bursts on the falling edge exceed the preset level threshold-. Element 9, it is triggered, and at its output, an asymmetry response signal appears (Fig. 3). This signal is fed to the second input of the pulse-width modulator 2, namely the comparator. Taking into account the control signal received from load 14, a signal is received at the output of the pulse pulse modulator (Fig. 3i), which is a sequence of rectangular pulses of different duration, In block 3 of the logical processing of the control signal, a bipolar converter The shoulder of the push-pull power amplifier 6, in which the asymmetry process occurred, decreases the duration of the signal at the base of the transistor of this shoulder and increases the resorption time of the main charge carriers. The diagrams of the signals on the bases of the transistors of the push-pull power amplifier are shown in fig.Zk, l. After that, the process of asymmetry disappears,

Thus, by performing a current sensor on the resistor, there is no need to make the coiled elements, which simplifies the design of the output transformer. This simplifies the threshold element, consisting of two resistors and one transistor, eliminating the need to use a threshold element with a detector rectifier,

In addition, by connecting the current sensor to the negative input terminal, it is possible to connect the collectors of the transistors of the output push-pull power amplifier to the positive input terminal, as a result, these transistors can be distributed to one heat sink without isolation,

By using less

the number of elements in the asymmetry protection device decreases overall dimensions, the inertia decreases, the speed increases, and the reliability increases.

Claims (1)

Invention Formula A voltage converter with protection from asymmetry, containing a push-pull power amplifier at transistors, the output of a square pulse generator, is connected to the first input of a pulse-width modulator and to the first input of the control logic processing unit, to the second input of which the output width is connected. pulse modulator, the first and second outputs of the logic control signal processing unit are connected to the corresponding transistor bases, in the power circuit of which a current sensor is included, the threshold input element is connected in parallel to the current sensor, and the output is connected to the second input of the ip pulse modulator, characterized in that, in order to increase reliability and speed, the collectors of the transistors are combined and connected to the first input terminal of the converter, and the current sensor is made on a resistor , one output of which is connected to the middle output of the primary winding of the high voltage transformer, the other output to the second input-output of the converter, the logic control signal processing unit is made with two additional components outputs and contains a counting B-trigger, whose input is the first input of the logical control signal processing unit, the first and second elements 2I-NOT, whose inputs are connected to the outputs of the counting D-trigger, and the second inputs are combined and are the second input control signal processing unit, and the outputs through the first and second transistor amplifiers to the terminals of the primary winding of the transformer, with the first and second outputs of the control signal processing unit connected to the bases of the corresponding transistor a push-pull power amplifier through a respective resistor and the third and fourth outputs are connected to the emitters of the respective transistors and respectively to first and second output terminals of the transformer primary winding. Yu s s R a five LTLnjnjnJTJTJ / account / h / / A / V -v at and fie.Z